Nickel in milled rice (Oryza sativa L.) from the three main rice-producing regions in China.

Nickel (Ni) concentrations in milled rice obtained from China and their variations among different provinces and varieties, as well as associated health risks, were investigated. Results showed that the mean Ni concentration in milled rice was 0.49 +/- 0.51mg/kg, which was much higher than reported in United Kingdom, French and Iranian cereals. There were significant variations (P<0.05) of Ni concentrations in milled rice among different provinces and among varieties in the same province. According to the dietary risk assessment, the mean values of the target hazard quotient for chronic risk ranged from 1.24 to 1.46 for 2-4, 4-7 and 7-11-year-old children, and all values of margin of exposure for hypersensitivity risk were considerably below 10 for all age groups, indicating that the current dietary exposure to Ni in rice is of concern for 2-11-year-old children and Ni-sensitised individuals. It is essential to establish a continuous monitoring programme to control Ni contamination in rice.